The expression $x^2 - 1$ is another example of the difference of squares. It can be factored using the formula:

$a^2 - b^2 = (a - b)(a + b)$

Here, $x^2$ is $a^2$ and 1 is $b^2$, where $b = 1$. So, the expression factors as:

$x^2 - 1 = (x - 1)(x + 1)$

Would you like more details or have any questions?

Here are 5 related questions:

1. How would you factor $x^2 - 4$?
2. What are the solutions to the equation $x^2 - 1 = 0$?
3. How does the difference of squares apply to $x^2 - 9$?
4. What if the expression was $x^2 + 1$ instead? Can it be factored?
5. How do you expand $(x - 1)(x + 1)$ to verify the factorization?

Tip: When dealing with a quadratic expression, always check if it can be factored using the difference of squares, especially when the constant term is a perfect square.